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BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: use-after-free in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:111 [inline]
BUG: KASAN: use-after-free in __refcount_add include/linux/refcount.h:193 [inline]
BUG: KASAN: use-after-free in __refcount_inc include/linux/refcount.h:250 [inline]
BUG: KASAN: use-after-free in refcount_inc include/linux/refcount.h:267 [inline]
BUG: KASAN: use-after-free in sock_hold include/net/sock.h:702 [inline]
BUG: KASAN: use-after-free in nr_release+0x62/0x450 net/netrom/af_netrom.c:520
Write of size 4 at addr ffff88807bdfa080 by task syz-executor774/31100

CPU: 0 PID: 31100 Comm: syz-executor774 Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
 print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:256
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
 atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:111 [inline]
 __refcount_add include/linux/refcount.h:193 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 sock_hold include/net/sock.h:702 [inline]
 nr_release+0x62/0x450 net/netrom/af_netrom.c:520
 __sock_release+0xcd/0x280 net/socket.c:649
 sock_close+0x18/0x20 net/socket.c:1314
 __fput+0x288/0x9f0 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0xbae/0x2a30 kernel/exit.c:825
 do_group_exit+0x125/0x310 kernel/exit.c:922
 get_signal+0x47f/0x2160 kernel/signal.c:2868
 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:865
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f38b0f936d9
Code: Unable to access opcode bytes at RIP 0x7f38b0f936af.
RSP: 002b:00007fff001aa888 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 00007f38b0f936d9
RDX: 00007f38b0f936d9 RSI: ffffffffffffffc0 RDI: 0000000040000000
RBP: 0000000000000003 R08: 000000000000000d R09: 000000000000000d
R10: 000000000000000d R11: 0000000000000246 R12: 00005555557af2c0
R13: 0000000000000000 R14: 000000000007ed88 R15: 00007fff001aa894

Allocated by task 31100:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 ____kasan_kmalloc mm/kasan/common.c:472 [inline]
 __kasan_kmalloc+0xa4/0xd0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:596 [inline]
 sk_prot_alloc+0x110/0x290 net/core/sock.c:1822
 sk_alloc+0x30/0xa60 net/core/sock.c:1875
 nr_create+0xb2/0x5f0 net/netrom/af_netrom.c:433
 __sock_create+0x353/0x790 net/socket.c:1464
 sock_create net/socket.c:1515 [inline]
 __sys_socket+0xef/0x200 net/socket.c:1557
 __do_sys_socket net/socket.c:1566 [inline]
 __se_sys_socket net/socket.c:1564 [inline]
 __x64_sys_socket+0x6f/0xb0 net/socket.c:1564
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 0:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free mm/kasan/common.c:328 [inline]
 __kasan_slab_free+0xff/0x130 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1628 [inline]
 slab_free_freelist_hook+0xe3/0x250 mm/slub.c:1653
 slab_free mm/slub.c:3213 [inline]
 kfree+0xe4/0x540 mm/slub.c:4267
 sk_prot_free net/core/sock.c:1858 [inline]
 __sk_destruct+0x6a8/0x900 net/core/sock.c:1943
 sk_destruct+0xbd/0xe0 net/core/sock.c:1958
 __sk_free+0xef/0x3d0 net/core/sock.c:1969
 sk_free+0x78/0xa0 net/core/sock.c:1980
 sock_put include/net/sock.h:1815 [inline]
 nr_heartbeat_expiry+0x2e7/0x460 net/netrom/nr_timer.c:148
 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421
 expire_timers kernel/time/timer.c:1466 [inline]
 __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734
 __run_timers kernel/time/timer.c:1715 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558

Last potentially related work creation:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_record_aux_stack+0xe9/0x110 mm/kasan/generic.c:348
 kvfree_call_rcu+0x74/0x990 kernel/rcu/tree.c:3552
 drop_sysctl_table+0x3c0/0x4e0 fs/proc/proc_sysctl.c:1647
 unregister_sysctl_table fs/proc/proc_sysctl.c:1685 [inline]
 unregister_sysctl_table+0xc2/0x190 fs/proc/proc_sysctl.c:1660
 __devinet_sysctl_unregister net/ipv4/devinet.c:2600 [inline]
 devinet_exit_net+0xe4/0x280 net/ipv4/devinet.c:2739
 ops_exit_list+0xb0/0x160 net/core/net_namespace.c:168
 cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:591
 process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

The buggy address belongs to the object at ffff88807bdfa000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 128 bytes inside of
 2048-byte region [ffff88807bdfa000, ffff88807bdfa800)
The buggy address belongs to the page:
page:ffffea0001ef7e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7bdf8
head:ffffea0001ef7e00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888010c42000
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 13438, ts 157614377167, free_ts 157510986812
 prep_new_page mm/page_alloc.c:2436 [inline]
 get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4168
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5390
 alloc_pages+0x1a7/0x300 mm/mempolicy.c:2291
 alloc_slab_page mm/slub.c:1691 [inline]
 allocate_slab+0x32e/0x4b0 mm/slub.c:1831
 new_slab mm/slub.c:1894 [inline]
 new_slab_objects mm/slub.c:2640 [inline]
 ___slab_alloc+0x473/0x7b0 mm/slub.c:2803
 __slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2843
 slab_alloc_node mm/slub.c:2925 [inline]
 __kmalloc_node_track_caller+0x2e3/0x360 mm/slub.c:4653
 kmalloc_reserve net/core/skbuff.c:355 [inline]
 __alloc_skb+0xde/0x340 net/core/skbuff.c:426
 alloc_skb include/linux/skbuff.h:1116 [inline]
 nlmsg_new include/net/netlink.h:953 [inline]
 rtmsg_ifinfo_build_skb+0x72/0x1a0 net/core/rtnetlink.c:3809
 unregister_netdevice_many+0x9e4/0x1790 net/core/dev.c:11043
 vti6_exit_batch_net+0x3a0/0x670 net/ipv6/ip6_vti.c:1188
 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:171
 setup_net+0x639/0xa30 net/core/net_namespace.c:349
 copy_net_ns+0x319/0x760 net/core/net_namespace.c:470
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1346 [inline]
 free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1397
 free_unref_page_prepare mm/page_alloc.c:3332 [inline]
 free_unref_page+0x19/0x690 mm/page_alloc.c:3411
 unfreeze_partials+0x16c/0x1b0 mm/slub.c:2421
 put_cpu_partial+0x13d/0x230 mm/slub.c:2457
 qlink_free mm/kasan/quarantine.c:146 [inline]
 qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165
 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272
 __kasan_slab_alloc+0x95/0xb0 mm/kasan/common.c:444
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook mm/slab.h:519 [inline]
 slab_alloc_node mm/slub.c:2959 [inline]
 slab_alloc mm/slub.c:2967 [inline]
 kmem_cache_alloc+0x285/0x4a0 mm/slub.c:2972
 prepare_kernel_cred+0x27/0x890 kernel/cred.c:724
 call_usermodehelper_exec_async+0x10e/0x580 kernel/umh.c:91
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Memory state around the buggy address:
 ffff88807bdf9f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88807bdfa000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807bdfa080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88807bdfa100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807bdfa180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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